MyoD is a master regulator for skeletal myogenesis in the sense that transduction of this gene is sufficient to activate the whole genetic program of muscle differentiation in non-muscle cells. The key element of the powerful transcriptional activity of the MyoD protein is the transactivation domain (TAD) located at the amino- terminus. It was recently found that fusion of the MyoD TAD to the pluripotency transcription factor Oct4 increases the efficiency of making induced pluripotent stem cells (iPSCs) more than 10-fold compared with the wild-type Oct4 when transduced with Sox2, Klf4, and c-Myc into fibroblasts. The MyoD TAD belongs to the acidic TAD family, which binds to many chromatin proteins and transcription factors that are necessary to activate target genes. In contrast, little is known abot long noncoding RNAs (lncRNAs) that interact with the MyoD TAD. Contribution of lncRNAs to myogeneis in general also remains elusive. LncRNAs are defined as RNA that are longer than 200 bases and do not encode mRNA, tRNA, or rRNA. LncRNAs are involved in almost every aspect of cell biology, including cell proliferation, differentiation, and tumor formation. Because lncRNAs bind to many chromatin proteins, the investigator hypothesized that the MyoD TAD uses lncRNAs to recruit these proteins to increase transcriptional activity. The long-term goal of the current project is to establish lncRNAs as novel key regulators of myogenesis. The investigator designed to isolate lncRNAs that are bound to the MyoD TAD by chromatin immunoprecipitation of MyoD and subsequent sequencing of associated RNAs. In addition, the investigator isolates lncRNAs that are bound to the fusion protein between the MyoD TAD and Oct4 but not to Oct4 itself. It was proposed to investigate the functions of one of the isolated lncRNA called TAR2 with the following three Aims. In Aim 1, target genes of TAR2 and its associated transcription factor Foxc1 will be identified and characterized genome-wide in myotubes with chromatin immunoprecipitation, gene knockdown, and RNA-seq. In Aim 2, the roles of TAR2 and Foxc1 in the formation of iPSCs prepared the MyoD TAD-fused Oct4 will be investigated. Aim 3 is designed to understand how the expression of TAR2, which is more highly expressed in muscle cells than in other cells, is regulated. These complementary studies are expected to establish TAR2 as a key effector of the MyoD TAD. This project will contribute to better understanding of myogenesis and iPSC formation through a novel viewpoint of lncRNA.